Sitting on a chair or a seating arrangement for longer periods of time can result in discomfort in the back, for example, the lower spine, shoulders and shoulder blades. Seating apparatus including vehicle seats subjected to prolonged and continuous usage demands adequate cushioning support for maintaining proper posture and providing enough comfort.
When a person is seated in a relatively upright position on a seating arrangement, the entire body weight of the person is distributed and supported on a relatively small support surface. Thus, the spring support or cushioning of the seating area must be correspondingly harder, firmer or stiffer in order to provide a comfortable support.
Polyurethane foam is commonly used cushioning material for seating arrangements. The polyurethane foam has a natural characteristic to become softer and softer with prolonged use, especially during usage in any seating application. In many cases, the foam breaks in within weeks and becomes much softer, which may lead to user discomfort due to in adequate cushioning support. Due to the changing characteristics of polyurethane foam, it is difficult to select the firmness of seat cushions in order to make it comfortable and supportive, even after prolonged usage.
Prior art methods of improved cushioning by including air bags positioned within a polyurethane cavity which would permit the ability to control the firmness of the seating area, but this method sacrifices the desirable characteristics of the polyurethane foam by replacing the foam with the air bags which have no desirable elements for achieving comfort on a seating surface.
In addition, seat cushion comprising inflatable element with arrangements such as baffles or channels that permits uniform distribution of force to foam can add to optimal support and comfort. Further, seats with adjustable firmness levels relying on desirable properties of polyurethane foam contribute to durability. In addition, seats provided with cushioning adjustable based on a desired level of user comfort and taste, allows a single seating arrangement to offer customized seating comfort for different individuals. For example, a husband of 200 lbs weight may require seating with increased cushion support than that of his wife of 100 lb weight, the adjustable cushion support allows each of them to adjust cushioning based on their own level of comfort.
U.S. Pat. No. 6,086,151 shows a chair apparatus for resilient support member which produces movement and force based on load applied. U.S. Pat. No. 6,609,753 shows a reclining passenger seat with cushioning properties adjusted based on seating or lying configuration of the seat. US patent publication no. 20140225405 shows an inflatable cushion seat used for sitting comfortably on a hard seat among bleachers. US patent publication no. 20050151410 shows chair with inflatable cellular insert connected to an electric pump device.
Although a number of seating arrangements employing a variety of cushioning options are available, it would be beneficial to provide an improved seating arrangement that includes user adjustable cushioning system that provides desired level of firmness thus resulting in a comfortable support while remaining in a seated position for a long time.